Anisotropic growth of nanomaterials has led to the development of complex and diverse nano-structures such as rods, tetrapods, prisms, cubes and additional shapes. These architectures display new properties and enrich the selection of nano-building blocks for electrical, optical and sensorial device construction. Even greater complexity and new function is introduced into the nanostructure by anisotropic growth with compositional variations. This has been elegantly realized by growing semiconductor heterostructures such as p-n junctions and material junctions in nanowires [1,2], and in the case of colloidal nanocrystals, in growth of rodlike CdSe/CdS core-shell particles [3] from spherical CdSe core nanocrystals and in complex branched growth.
A process for the preparation of nanocrystalline semiconductors, having rod-like shape of controlled dimensions is described in U.S. Pat. No. 5,505,928 [13] and in WO 03/097904 [4] for especially Group III-V semiconductors, [4]. Nanocrystal particles having core with first crystal structure, and at least one arm with second crystal structure are described in WO 03/054953 [5].
Recently there have been several reports relating to connectivity formation for micron-long quasi-one-dimensional structures such as nanotubes and nanowires [6, 7, 8]. However, wiring of shorter semiconductor nanoparticles such as rods and tetrapods, with arm lengths of less then 100 nm has not been achieved yet.